Door latches

ABSTRACT

A tubular mortice latch has a slam bolt slidable within a tubular body under the action of a rotary actuator. The rotary actuator, bolt and a spring acting on the bolt are formed as a sub-assembly insertable as a unit into the body thereby simplifying manufacture of the latch. The spring may be doubleacting in that it acts on the one hand to urge the bolt towards its latching position and acts on the other hand on the actuator to urge it towards its normal resting position.

United States Patent 1191 James 1 DOOR LATCHES [75] Inventor: MichaelJoseph James, Cheltenham,

England Micro & Precision Mouldings (Cheltenham Limited), Cheltenham,England [22] Filed: July 16, 1973 [21] Appl. No.: 379,434

[73] Assignee:

[30] Foreign Application Priority Data July 19.1972 United Kingdom33701/72 [52] US. Cl 292/169; 292/l69.l6 [51] Int. Cl. EOSC 1/12 [58]Field of Search 292/D1G. 38, 169.

[56] References Cited UNITED STATES PATENTS 9/1912 Anderson ..292/169.l6

[451 Sept. 30, 1975 1.559.037 10/1925 Floyd 292/169.16 1.871.633 8/1932Ter Meer 292/169 X 3.459.448 8/1969 Russell et a1. 292/169 X 3,544,14712/1970 James 292/169 3,580,622 5/1971 Morgan 292/169 3,655.230 4/1972Armstrong 292/169 Primary Examiner-Roy D. Frazier AssistantEtaminer-Peter A. Aschenbrenner Attorney, Agent, or Firm-Young &Thompson 57 1 ABSTRACT 9 Claims, 9 Drawing Figures DOOR LATCHES FIELD OFTHE INVENTION This invention relates to door latches of the tubularmortice type. Such a latch has a tubular body for fitting into the door,a slam bolt slidable in the body and spring loaded to a projectinglatching position, and a rotary actuator mounted within the body forrotary connection to a door handle. Turning of the actuator by thehandle, about an axis at right angles to the bolt axis, in use acts todraw the bolt into the body to a release position.

SUMMARY OF THE INVENTION A mortice latch assembly comprises a tubularbody and a sub-assembly, including a bolt, bolt-spring and rotaryactuator, fitted as such through one end of the body, the parts of thesub-assembly being held together by engagement of an operatingprojection of the actuator with the bolt.

Preferably the sub-assembly includes all the parts of the latch otherthan the body, and all parts other than the spring are convenientlyplastics mouldings. The body may be a one-piece moulding closed at theinner end, the sub-assembly being fitted into the body through the outerend aperture from which the bolt projects for latching purposes. Theactuator may have snap-in engagement with'the body to retain thesubassembly, and this engagement may be between side bearing bosses onthe actuator and bearing apertures or surfaces in the body moulding.

The invention also provides a mortice latch assembly comprising atubular body, a slam bolt slidable in the body between a projectinglatching position and a drawn back release position, a rotary actuatormounted in the body and which engages the bolt to move the latter to therelease position, and a bolt spring which on the one hand acts on thebolt to urge the latter towards the latching position and on the otherhand acts on the actuator to urge the latter towards a normal restingposition or to retain it in that position.

The latch assembly preferably includes a follower which provides aspring abutment and engages the actuator to transmit the spring forcethereto, and this follower may slidably engage the body. The rotaryactuator is preferably double acting, i.e. turnable in either directionto release the latch, with a central resting position and it may have aprojecting limb which has snap-in engagement with the bolt for operativeconnection thereto.

The bolt and the follower are preferably formed with profiled surfaces,that on the bolt being engaged by the actuator limb with a camrningaction for bolt withdrawal and that on the follower engaging theactuator limb to urge the latter to said resting position. Engagement ofthe actuator limb with the bolt may employ the resilience of the boltmaterial to provide said snap-in engagement, and it may serve to holdthe bolt, spring, follower and actuator together as a unitarysubassembly which can be fitted as such into the body.

Use of the bolt spring to provide a return force urging the actuator toits resting position provides a very simple and compact arrangementsuitable for use with socalled continental door furniture with'handlesets which do not include handle return springs, and in this case thespring return of the actuator also provides the handle return force. Thefitting of the movable parts of the latch as a sub-assembly, retained assuch by mere inter-engagement of the actuator and the bolts, providesvery rapid and easy assembly which is reflected in low overallmanufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an outer end view of theassembly,

FIG. 2 is a sectional view on the line II II in FIG.

FIG. 3 is a sectional view on the line III III in FIG.

1, FIG. 4 is a sectional view on the line IV IV in FIG.

FIG. 5 is a detail view of a body of the assembly,

FIG. 6 is a detail sectional view on the line VI VI in FIG. 2, of a boltof the assembly, I

FIG. 7 is a detail sectional view on the line VII VII in FIG. 6, and

FIG. 8 is a detail sectional view on the line VIII VIII in FIG. 6, and

FIG. 9 is a detail view of a follower of the assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT A one-piece tubular moulded body1 has a rectangular outer end fixing flange land is closed at the innerend. Considering the flange 2 mounted in the normal manner (as shown inthe drawings) with its major axis vertical, the body 1 has flat parallelside walls 3 joined by concentric arcuate top and bottom walls 4, thesebeing continuous from side bearing apertures 5 in the body through tothe outer end aperture 6 from which a slam bolt 7 projects for latchingpurposes.

The slam bolt 7 has a normal nose profile for engagement with acomplementary keeper (not shown) and from the nose portion 8, which ishollow, has parallel spaced side limbs 9 which extend into the body 1and slidably engage the side walls 3 thereof. A rotary actuator 10 hasopposed bearing bosses l2, and the bearing apertures 5 in the body 1,see particularly FIG. 5, are elongated axially of the body 1 with curvedends providing effective inner and outer arcuate bearing surfaces 5a and5b which are laterally offset and engaged by the bearing bosses 12.

The actuator 10 has an outwardly projecting limb 13 which tapers towardsthe free end at which it has opposed side projections 14, in the form ofcircular stubs which respectively engage generally V-shaped ca'mmingsurfaces 15 formed internally on the bolt limbs 9 adjacent to the innerfree ends thereof. A follower moulding 16 has a central portion 17extending vertically within the housing and which has a sliding fitbetween the bolt limbs 9 which, as shown more particularly inFIG. 8, areof channel section. At each end this portion has inwardly and outwardlyprojecting limbs 18 which slidably engage the upper and lower walls 4 ofthe body 1, and it also has a central outward projection 19 which fitsinto and locates the inner end of a spring 20 the outer end of whichlocates within the hollow bolt nose 8.

The follower 16 also has two side projections 22 which provide snap-ininitial fitting between the bolt limbs 9 before the bolt 7 is fitted tothe actuator 10, the follower 16 acting as a spring abutment andtransmitting the spring force to the actuator 10 during latch operation.On assembly, the projections 22 snap into position past inner end walls21 on the bolt limbs 9 and on which the profiles 15 are formed. On itsinner side the main portion 17 of the follower (see FIG. 3) has a V-shaped camming profile 23, opposite but generally similar to that of thebolt limbs 9, and this engages a radiused end of the actuator limb 13.

The assembly of the described latch is particularly rapid and simple.The spring 20 is placed between the bolt limbs 9 and is located on andcompressed by the follower 16 as the latter is snapped into positionbetween the limbs 9. The actuator 10 is now fitted, its projecting limb13 being inserted between the bolt limbs 9 and snapped into positionpast the end walls 21 in operative engagement with the bolt cammingsurfaces 15 while at the same time engaged by the follower cammingsurface 23. This completes a sub-assembly of all the movable parts ofthe latch, this sub-assembly -then being inserted into the outer end ofthe housing 1 and pushed home until projections 24 on the bearing bosses12 snap into engagement with said outer bearing surfaces b, therebyretaining the sub-assembly within the body 1.

The actuator has a throughbore 25 of square section to accept the usualsquare-section shaft (not shown) interconnecting inner and outer doorhandles (also not shown). Turning of the actuator by the shaft causesthe actuator stubs 14 to move along the cam surfaces on the bolt 7, thecamming action withdrawing the bolt 7 into the body 1 against thespring'force. Angular movement of the actuator 10 is limited byengagement of side faces 26 of a projecting tail portion 27 of theactuator with the top and bottom walls 4 of the body 1 inwardly of thebearing apertures 5.

As the actuator stubs 14 move along the camming surfaces 15 of the bolt7 they similarly move along the camming surface 23 on the follower 16,which thus tranmits the spring force to the double-acting actuator 10with a centring action. This acts to return the actuator to the restingposition illustrated, and can also provide the return force for unspringhandle sets; as will be appreciated this centring action is present inall bolt positions. At the limit of angular movement, the actuator limb13 reaches the corresponding ends of each camming surface 15 and 23,thereby assisting in limiting the angular movement by engagement of theactuator limb 13 with the corresponding limb 18 of the follower 16. Thusthe angular movement is limited in a solid manner by reaction with thebody I on both sides of the shaft, providing a very strong construction.

What is claimed is:

l. A mortice latch assembly comprising a tubular body and a subassemblyinsertable as a unit through one end of said tubular body, saidsubassembly com prising a slam bolt and a bolt spring and a follower anda rotary actuator, the bolt being slidable in the body between a forwardprojecting latching position and a rear retracted release position, theactuator seating on the body for angular movement transverse to thedirection of bolt sliding movement, the bolt having side limbs thatextend rearwardly from a front nose portion of the bolt, the followerbeing slidable in the body between the bolt limbs, the spring beingdisposed between the bolt limbs and acting in compression between therear of the bolt nose and the front of the follower, the actuator,having an operating projection between the bolt limbs that engages withthe bolt limbs to hold the subassembly together for fitting into thebody, the bolt limbs having cam surfaces thereon that contact theactuator projection and that are inclined to the direction of boltsliding movement so that rotation of the actuator in one direction froma rest position moves the bolt rearwardly, the follower having a camsurface thereon that contacts the actuator projection and that isinclined to the direction of bolt sliding movement and oppositelyinclined to the cam surfaces of the bolt limbs so that rotation of theactuator in said one direction from said rest position moves thefollower forwardly.

2. A latch assembly as claimed in claim 1, wherein the actuator has asnap-in engagement with the body to retain the said assembly within thebody.

3. A latch assembly as claimed in claim 2, wherein said snap-inengagement is between side bearing bosses on the actuator and bearingsurfaces on the body.

4. A latch assembly as claimed in claim 20, in which the follower has aninitial snap-in engagement with the bolt limbs to facilitate assembly ofthe subassembly.

5. A latch assembly as claimed in claim 1, in which the actuator isdouble acting and said rest position is a centered position of theactuator projection in the body.

6. A latch assembly as claimed in claim 1, in which the actuatorprojection has snap-in engagement with the bolt for operative connectionthereto.

7. A latch assembly as claimed in claim 1, in which the actuatorprojection has oppositely projecting stubs which engage the inclined camsurfaces of the bolt limbs and of the follower.

8. A latch assembly as claimed in claim 1, in which the cam surfaces onthe bolt limbs are forwardly concave and the cam surface on the followeris rearwardly concave.

9. A latch assembly as claimed in claim 8, in which the cam surfaces aresubstantially V-shaped.

1. A mortice latch assembly comprising a tubular body and a subassemblyinsertable as a unit through one end of said tubular body, saidsubassembly comprising a slam bolt and a bolt spring and a follower anda rotary actuator, the bolt being slidable in the body between a forwardprojecting latching position and a rear retracted release position, theactuator seating on the body for angular movement transverse to thedirection of bolt sliding movement, the bolt having side limbs thatextend rearwardly from a front nose portion of the bolt, the followerbeing slidable in the body between the bolt limbs, the spring beingdisposed between the bolt limbs and acting in compression between therear of the bolt nose and the front of the follower, the actuator,having an operating projection between the bolt limbs that engages withthe bolt limbs to hold the subassembly together for fitting into thebody, the bolt limbs having cam surfaces thereon that contact theactuator projection and that are inclined to the direction of boltsliding movement so that rotation of the actuator in one direction froma rest position moves the bolt rearwardly, the follower having a camsurface thereon that contacts the actuator projection and that isinclined to the direction of bolt sliding movement and oppositelyinclined to the cam surfaces of the bolt limbs so that rotation of theactuator in said one direction from said rest position moves thefollower forwardly.
 2. A latch assembly as claimed in claim 1, whereinthe actuator has a snap-in engagement with the body to retain the saidassembly within the body.
 3. A latch assembly as claimed in claim 2,wherein said snap-in engagement is between side bearing bosses on theactuator and bearing surfaces on the body.
 4. A latch assembly asclaimed in claim 20, in which the follower has an initial snap-inengagement with the bolt limbs to facilitate assembly of thesubassembly.
 5. A latch assembly as claimed in claim 1, in which theactuator is double acting and said rest position is a centered positionof the actuator projection in the body.
 6. A latch assembly as claimedin claim 1, in which the actuator projection has snap-in engagement withthe bolt for operative connection thereto.
 7. A latch assembly asclaimed in claim 1, in which the actuator projection has oppositelyprojecting stubs which engage the inclined cam surfaces of the boltlimbs and of the follower.
 8. A latch assembly as claimed in claim 1, inwhich the cam surfaces on the bolt limbs are forwardly concave and thecam surface on the follower is rearwardly concave.
 9. A latch assemblyas claimed in claim 8, in which the cam surfaces are substantiallyV-shaped.